Here's a photo of him kneeling and bowing his head to receive the blessing of Protestant ministers along with Fr. Raniero Cantalamessa.

You are mistaken. In actuality, Cardinal Bergoglio knelt down to receive the blessing of Fr. Cantalamessa. The Protestants decided to join in. What was the Cardinal supposed to do at that point? Make a scene in front of a large audience? Or take the risk that uncharitable folk in the future would distort what actually happened?